breastUS - SONOGRAPHIC CHARACTERISTICS

SONOGRAPHIC CHARACTERISTICS - BREAST MASSES

Margins

Should be investigated carefully
Technique called Fremitus can be used to identify and confirm margins
- Fremitus - refers to vibrations produced by phonation and felt through the chest wall during palpation; a technique used in conjunction with power doppler to identifiy the margins of a lesion
- Have the patient hum
Benign lesions usually have smooth, rounded margins
Malignancies are aggressive and tend to grow through tissue via spiculation
- Spiculation - finger-like extension of a malignant tumor; usually appears as a small line that radiates outward from the margin of a mass
Spiculated margins are the U/S finding with the highest positive predictive value of malignancy
- Typically alternating hypoechoic and hyperechoic lines

The mass is irregular, hypoechoic and has an echogenic halo and spiculated margins (arrows).

Disruption of Breast Architecture

Benign tumors are usually slow growing and do not invade surrounding tissue
- They tend to grow horizontally within the tissue planes, parallel to the chest wall
- Large bening lesions may cause compression of adjacent tissue
  - Do not confuse this with infiltrating

Malignant Lesions tend to grow right through the normal breast tissue
- As masses enlarge they may cause retraction of the nipple or dimpling of the skin as the spiculation pull on the Cooper's Ligaments

Shape

Benign
- Rounded or oval shape is usually associated with benign lesions
- Mild undulations in contour
- Larger, rounded lobulation -- not exceeding 3 in number
Malignant
- Sharp, angular margins are associated with malignancy
- Microlobulations (1-2mm) -- smaller, sharper, numerous

Orientation

Normal tissue planes of the breast are horizontally oriented
Benign lesions tend to grow within the normal tissue planes, long axis lying parallel to chest wall
Malignant lesions are able to grow through the connective tissue and may have a vertical orientation when imaging A/P
If a mass measures longer in the A/P dimension than in either sagittal or transverse it is described as "taller than wide"
- Suspicious for malignancy

Internal Echo Pattern

Benign
- Isoechoic with breast parenchyma or have echoes equivalent to or brighter than fat

Malignant
- Hypoechoic
- Weak internal echoes
- Dense posterior shadowing - making lesion difficult to penetrate
- Microcalcifications within mass

MALIGNANT

BENIGN

Attenuation Effects

Mobility, Compressibility, and Vascularity

Mobility

Compressibility

Vascularity

Essential element of study
Malignant masses will often demonstrate increased vascularity with the lesion
- Often have a feeder vessel -- can be identified with careful evaluation
Check with power doppler to determine number of vessels feeding and also look for intratumoral vessels